SE-0246: Protocols and static functions (#23824)

This implements the protocols and static functions proposed in SE-0246, plus some initial test coverage. It also has some rough accompanying cleanup of tgmath. It does not include the globals (on scalars or SIMD types) nor does it deprecate much in tgmath.h.

utils/SwiftMathFunctions.py

@@ -0,0 +1,85 @@
+class SwiftMathFunction(object):
+    def __init__(self, name, kind=None, swiftName=None, args="x", comment=None,
+                 platforms=None):
+        self.name = name
+        self.swiftName = swiftName if swiftName is not None else name
+        self.kind = kind if kind is not None else "library"
+        self.args = args
+        if comment is not None:
+            self.comment = comment
+        else:
+            self.comment = "/// The " + str(self.swiftName) + " function."
+        self.platforms = platforms
+
+    def params(self, prefix="", suffix=""):
+        return ", ".join(map(lambda a: prefix + a + suffix, self.args))
+
+    def decl(self, type):
+        return self.swiftName + "(" + self.params("_ ", ": " + type) + \
+            ") -> " + type
+
+    def free_decl(self, constraint="T: ElementaryFunctions"):
+        return self.swiftName + "<T>(" + self.params("_ ", ": T") + \
+            ") -> T where " + constraint
+
+    def impl(self, type):
+        if self.kind == "intrinsic":
+            builtin = "Builtin.int_" + self.name + "_FPIEEE" + str(type.bits)
+            return type.stdlib_name + "(" + builtin + "(" + \
+                self.params("", "._value") + "))"
+        return "_swift_stdlib_" + self.name + type.cFuncSuffix + "(" + \
+            self.params() + ")"
+
+
+ElementaryFunctions = [
+    SwiftMathFunction(name="sqrt", kind="intrinsic", comment="""
+  /// The square root of `x`.
+  ///
+  /// For real types, if the argument is negative, either the result is NaN
+  /// or a precondition failure occurs. For complex types, this function has
+  /// a branch cut along the negative real axis.
+"""),
+    SwiftMathFunction(name="cos", kind="intrinsic", comment="""
+  /// The cosine of `x`.
+  ///
+  /// For real types, `x` is interpreted as an angle measured in radians.
+"""),
+    SwiftMathFunction(name="sin", kind="intrinsic", comment="""
+  /// The sine of `x`.
+  ///
+  /// For real types, `x` is interpreted as an angle measured in radians.
+"""),
+    SwiftMathFunction(name="tan",
+                      comment="/// The tangent of `x`."),
+    SwiftMathFunction(name="acos"),
+    SwiftMathFunction(name="asin"),
+    SwiftMathFunction(name="atan"),
+    SwiftMathFunction(name="cosh"),
+    SwiftMathFunction(name="sinh"),
+    SwiftMathFunction(name="tanh"),
+    SwiftMathFunction(name="acosh"),
+    SwiftMathFunction(name="asinh"),
+    SwiftMathFunction(name="atanh"),
+    SwiftMathFunction(name="exp", kind="intrinsic"),
+    SwiftMathFunction(name="exp2", kind="intrinsic"),
+    SwiftMathFunction(name="exp10"),
+    SwiftMathFunction(name="expm1"),
+    SwiftMathFunction(name="log", kind="intrinsic"),
+    SwiftMathFunction(name="log2", kind="intrinsic"),
+    SwiftMathFunction(name="log10", kind="intrinsic"),
+    SwiftMathFunction(name="log1p"),
+    # SwiftMathFunction(name="pow", kind="intrinsic", args="xy"), Handled
+    # separately for edge cases.
+    # SwiftMathFunction(name="root", args="xn"), Handled separately for
+    # implementation.
+]
+
+RealFunctions = [
+    # SwiftMathFunction(name="atan2"), Handled separately for explicit
+    # argument labels.
+    SwiftMathFunction(name="erf"),
+    SwiftMathFunction(name="erfc"),
+    SwiftMathFunction(name="hypot", args="xy"),
+    SwiftMathFunction(name="tgamma", swiftName="gamma"),
+    # SwiftMathFunction(name="lgamma"), Handled separately for sign result.
+]